The sign says:
Caution (in big letters)

This sign has (in smaller letters, but still big enough to be made out clearly)

Sharp edges (huge lettering)

Do not touch the edges of this sign (in much smaller letters)

Also, the bridge is out ahead (in really tiny letters, you cannot even tell what it says in this image. The only reason I know is because I found it elsewhere)

Then the cation says:
Safety (in big letters)

That's how we do things in America (in smaller letters

QotD: Favorite song?